There are many reasons for her depression and suicide, such as unemployment (the supervisor seems to be kind, but in fact she is selfish and indifferent, forcing Hu Jingjing to resign voluntarily, just to save compensation), lovelorn (the day before suicide, she ended her three-month relationship), and smart Jingjing can definitely feel Rei Lin's behavior of treating her as a spare tire (in the process of unrequited love, plus her status as a best friend, she suffered a lot) and owing money (operating on her mother, she owed money).
However, I think the root cause of her depression and suicide comes from her family background. Hu Jingjing's mother in the play was introduced by Ji Nanjia's mother.
Hu Jingjing, who has just come to Beijing to work, not only has to pay the rent and various living expenses in big cities, but also keeps sending money to her family, including her mother's hospitalization for surgery, changing rooms at home, and the weddings and funerals of relatives. On the one hand, Jingjing's own personality is relatively strong, on the other hand, it has a lot to do with her mother.
Character determines fate, and this sentence really has its truth. Hu Jingjing's depressed suicide is largely determined by her personality. She always shows the good optimism and positive side outside, and accumulates all the bad emotions in her own psychology (in the words of Ji Nanjia's mother, it is too strong). Finally, after a series of blows, she couldn't hold on.
Finally, I want to say that if you are lucky enough to live in a happy family in Descendants, just like Joe and Ouyang in TV series, congratulations, you are one of thousands of people. If your family is unhappy, like Hu Jingjing, you should learn to heal yourself. Although it is difficult, you should work hard.